DESCRIPTION: Our goal in this project is to develop a web-application to guide researchers in the efficient and effective design of animal studies that balance the competing needs of minimizing animal use and providing rigorous, repeatable results. Three basic ideas, which translate directly into our three specific aims, form the foundation of our proposed tool. First an foremost is to place science before statistics: develop the science plan for a pilot, exploratory o hypothesis-driven study with a clear idea of the effects of interest and structure of the animal selection, housing, and treatment plan. Second is a prospective examination of sample size and effect size through power computations. Third is ready access to expert support with design and statistics professionals. The proposed study is the first phase in the development of a web-application for experimental design and analysis. Our Phase I effort will demonstrate the concept with a prototype dynamic web application that provides qualitative and quantitative decision support together with person-to-person on-line chat capability for rapid technical assistance with study design. In collaboration with our teammates at UC San Diego and UC Davis, we will develop a set of example case studies from their extensive animal research experience, ranging both in study goals and problem complexity. From these examples, we will develop use cases to design the user-system interactions that will form the software development foundation.